1. Field of the Invention
The present invention relates to a plasma display panel. More particularly, the present invention pertains to a plasma display panel that may enhance a light emission uniformity of discharge cells, even when electrodes are formed with nontransparent bus lines.
2. Description of Related Art
Generally, a plasma display panel (PDP) is a display device that may display an image using red, green and blue visible light created by exciting phosphors using vacuum ultraviolet (VUV) rays emitted from a plasma-generated gas discharge.
In an alternating current (AC) plasma display panel, address electrodes may be formed on a rear substrate. The address electrodes may be covered by a dielectric layer. Barrier ribs may be are arranged in a stripe pattern on the dielectric layer between the address electrodes. Red, green and blue phosphor layers may be formed on the barrier ribs. Multiple display panels, each having a pair of sustain and scan electrodes, may be arranged on a surface opposite to the front surface or the rear surface. The display electrodes may extend in a direction crossing the address electrodes. The display electrodes may be covered by a dielectric layer and an MgO passivation layer. Discharge may be are formed at regions where the address electrodes formed on the rear substrate cross the sustain and scan electrodes formed on the front substrate. Typically, millions of the discharge cells may be arranged in a matrix pattern in the plasma display panel.
A memory property may be used for driving the discharge cells of the plasma display panel. In order to generate the discharge between the sustain and scan electrodes, a potential difference higher than a specific voltage may be required. This boundary voltage may be called a firing voltage (Vf). When scan and address voltages are respectively applied to the scan and address electrodes, the discharge may be generated between the scan and address electrodes to generate plasma in the discharge cell. Electrons and ions of the plasma may travel to electrodes having polarities opposite to those of the electrons and ions.
A dielectric layer may be deposited on each electrode of the plasma display panel so that most of space charges may accumulate on the dielectric layer having an opposite polarity. As a result, since net space potential between the scan and address electrodes is to be lower than an initially applied address voltage (Va), the address discharge may weaken and disappear. At this point, a relatively small amount of electrons may accumulate on the sustain electrodes and a relatively large amount of electrons may accumulate on the scan electrodes. The charges accumulated on the dielectric layer covering the sustain and scan electrodes may be called wall charges (Qw). A space voltage generated between the sustain and scan electrodes by the wall charges may be called a wall voltage (Vw).
When a discharge sustain voltage (Vs) is applied to the sustain and scan electrodes, and a sum (Vs+Vw) of the discharge sustain voltage (Vs) and the wall voltage (Vw) is higher than the firing voltage (Vf), a sustain discharge may occur in the discharge cells to thereby generate vacuum ultraviolet. The vacuum ultraviolet may excite the corresponding phosphor layer to emit visible light through the transparent front panel.
However, when there is no address discharge between the scan and address electrodes, i.e., when no address voltage (Va) is applied, the wall charges may not accumulate between the sustain and scan electrodes. As a result, no wall voltage may exist between the sustain and scan electrodes. At this point, only the discharge sustain voltage (Vs) applied to the sustain and scan electrodes may be formed in the discharge cells. Since the discharge sustain voltage may be lower than the firing voltage (Vf), the gas space defined between the sustain and scan electrodes may not discharge.
The general plasma display panel may include an active region (a discharge region) emitting visible light using a sustain discharge in the discharge cells. The general plasma display panel may also include an inactive region (a non-discharge region), defined between adjacent discharge cells, which may not emit visible light. The non-discharge region may include a black portion, e.g., a black stripe, to enhance bright room contrast of the plasma display panel by absorbing external light. The black stripe may be formed through a process that is independent from a process for forming the sustain and scan electrodes, thereby making the manufacturing process of the plasma display panel complicated.
A piece of black stripe formed on the inactive region between the adjacent discharge cells may define a first gap by being spaced apart from a sustain electrode of one of the adjacent discharge cells. The piece of black stripe may also define a second gap by being spaced apart from a scan electrode of the other of the adjacent discharge cells. Since two gaps may be formed in one inactive region, it may thus be difficult to enlarge an area of the black portion in a limited area of the inactive area.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.